A texturing system for use in a three-dimensional graphics system has an input for receiving object data for an object to be textured. Encrypted texture data is obtained from a store a decrypted in a decryption unit. The decrypted texture data generates texture image data for a frame buffer from where it can be output for display.There is also provides a method for producing a software application for use in a three-dimensional graphics system which creates instructions for a software application and creates static texture data for use in conjunction with the instructions. The static texture data is encrypted and provided as encrypted texture data with the software instructions.A protected software application can be distributed to a target device from a distribution device by coupling the distribution device to the target device, transferring target device identifier data from the target device to the distribution device and using the target device identifier data in the distribution device to generate encryption definition data specific to the target device. The protected software application and encryption definition data are then transferred to the target device.